Presently, most truck operating condition monitoring systems converge behind the dashboard resulting in a kludge of a large number of wires from multiple sources. Typically, a truck dashboard may receive 260 individual wires totalling more than a 1,000 feet of wire. As a result, dashboard assembly, installation, troubleshooting and repair is increasingly difficult. Increasing customer demands for trip recorders, pager systems, satellite communications and the like will further complicate dashboard wiring requirements.
In current truck dashboards, each gauge usually is both dedicated and hardwired to a particular sensor in the truck. So that the fuel level gauge, for example, can only be coupled to the fuel level sensor. As a result, replacement inventories must include each type of dedicated gauge since there is no uniformity among gauges. Further, the fuel level gauge must remain in the same location on the dashboard absent substantial behind the dashboard rewiring.
A solution to the uniformity problem is offered in U.S. Pat. No. 4,551,801 issued Nov. 5, 1985 to Sokol. The gauges comprise identical programmable modules with separate scale plates. Each module is capable of displaying information from up to 16 different sensors to which the module is hardwired. The modules are programmed by input of a sensor identification code by means of either dip switches on the module or an external source. Although the Sokol gauges are not dedicated to a particular sensor which reduces inventory, each module is still hardwired to a particular group of sensors. Thus, the dashboard wiring is still overly complex.
Monitoring gauges and warning lights account for the largest fraction of dashboard wires. In 1994, the majority of truck diesel engines will utilize a programmable electronic control system operating on a standard (J1708/J1939 interface) data bus in order to increase fuel efficiency. During engine operation, the data bus will transmit the function and condition information in order to control engine operation.
None of the current gauge systems is constructed in a manner which would enable one to take advantage of the potential of using the operational information on the data bus of programmable electronic engine control systems. The system and method of the present invention provides a novel, programmable dashboard gauge system and method which takes full advantage of engine control system data buses and effects a very substantial reduction in dashboard wiring complexity. Identical modules are used to display monitoring gauge information and warning light information in response to information received along a standard data bus, which can include the engine control information. A scale plate is mounted to each gauge which identifies the gauge and causes it to display the data on the data bus from a particular sensor.